Vehicle power supply apparatus

ABSTRACT

A vehicle power supply apparatus includes first and second power supply systems, first and second switches, and a fail-safe controller. The second power supply system includes a generator motor coupled to an engine, and a second electrical energy accumulator able to be coupled to the generator motor. The fail-safe controller inhibits a powering state of the generator motor on the condition that the second switch is in a malfunctioning state in which the second switch is rendered inoperative in a second turn-on state. The second turn-on state includes coupling the generator motor and the second electrical energy accumulator to each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No.2018-120679 filed on Jun. 26, 2018, the entire contents of which arehereby incorporated by reference.

BACKGROUND

The technology relates to a vehicle power supply apparatus to be mountedon a vehicle.

A vehicle power supply apparatus to be mounted on a vehicle includes notonly an accumulator such as a lead battery and a lithium ion battery butalso a generator motor such as a motor generator and an integratedstarter generator (ISG). For example, reference can be made to JapaneseUnexamined Patent Application Publication (JP-A) Nos. 2013-189944,2016-193634, and 2017-114303. Moreover, such a vehicle power supplyapparatus is provided with a switch in order to control a coupling stateof the accumulator and the generator motor. The switch includes, forexample, semiconductor. The switch of the vehicle power supply apparatusis controlled to an ON state and an OFF state in accordance with anoperation state of the generator motor.

SUMMARY

An aspect of the technology provides a vehicle power supply apparatus tobe mounted on a vehicle that includes an engine. The vehicle powersupply apparatus includes a first power supply system, a second powersupply system, a first switch, a second switch, and a fail-safecontroller. The first power supply system includes a first electricalenergy accumulator and an electric load coupled to the first electricalenergy accumulator. The second power supply system includes a generatormotor and a second electrical energy accumulator. The generator motor iscoupled to the engine and is configured to be controlled to at least apowering state. The second electrical energy accumulator is able to becoupled to the generator motor. The first switch is configured to becontrolled to a first turn-on state and a first turn-off state. Thefirst turn-on state includes coupling the first power supply system andthe second power supply system to each other, and the first turn-offstate includes isolating the first power supply system and the secondpower supply system from each other. The second switch is configured tobe controlled to a second turn-on state and a second turn-off state. Thesecond turn-on state includes coupling the generator motor and thesecond electrical energy accumulator to each other, and the secondturn-off state includes isolating the generator motor and the secondelectrical energy accumulator from each other. The fail-safe controlleris configured to inhibit the powering state of the generator motor onthe condition that the second switch is in a malfunctioning state inwhich the second switch is rendered inoperative in the second turn-onstate.

An aspect of the technology provides a vehicle power supply apparatus tobe mounted on a vehicle that includes an engine. The vehicle powersupply apparatus includes a first power supply system, a second powersupply system, a first switch, a second switch, and a generator motorcontroller. The first power supply system includes a first electricalenergy accumulator and an electric load coupled to the first electricalenergy accumulator. The second power supply system includes a generatormotor and a second electrical energy accumulator. The generator motor iscoupled to the engine. The second electrical energy accumulator is ableto be coupled to the generator motor. The first switch is configured tobe controlled to a first turn-on state and a first turn-off state. Thefirst turn-on state includes coupling the first power supply system andthe second power supply system to each other, and the first turn-offstate includes isolating the first power supply system and the secondpower supply system from each other. The second switch is configured tobe controlled to a second turn-on state and a second turn-off state. Thesecond turn-on state includes coupling the generator motor and thesecond electrical energy accumulator to each other, and the secondturn-off state includes isolating the generator motor and the secondelectrical energy accumulator from each other. The generator motorcontroller is configured to control the generator motor to a powergeneration state on the condition that a state of charge of the secondelectrical energy accumulator is lower than a power generationthreshold. The power generation threshold is set at a first powergeneration threshold on the condition that the second switch is in anormal state. The power generation threshold is set at a second powergeneration threshold greater than the first power generation thresholdon the condition that the second switch is in a malfunctioning state inwhich the second switch is rendered inoperative in the second turn-onstate. An aspect of the technology provides a vehicle power supplyapparatus to be mounted on a vehicle that includes an engine. Thevehicle power supply apparatus includes a first power supply system, asecond power supply system, a first switch, a second switch, andcircuitry. The first power supply system includes a first electricalenergy accumulator and an electric load coupled to the first electricalenergy accumulator. The second power supply system includes a generatormotor and a second electrical energy accumulator. The generator motor iscoupled to the engine and is configured to be controlled to at least apowering state. The second electrical energy accumulator is able to becoupled to the generator motor. The first switch is configured to becontrolled to a first turn-on state and a first turn-off state. Thefirst turn-on state includes coupling the first power supply system andthe second power supply system to each other, and the first turn-offstate includes isolating the first power supply system and the secondpower supply system from each other. The second switch is configured tobe controlled to a second turn-on state and a second turn-off state. Thesecond turn-on state includes coupling the generator motor and thesecond electrical energy accumulator to each other, and the secondturn-off state includes isolating the generator motor and the secondelectrical energy accumulator from each other. The circuitry isconfigured to inhibit the powering state of the generator motor on thecondition that the second switch is in a malfunctioning state in whichthe second switch is rendered inoperative in the second turn-on state.

An aspect of the technology provides a vehicle power supply apparatus tobe mounted on a vehicle that includes an engine. The vehicle powersupply apparatus includes a first power supply system, a second powersupply system, a first switch, a second switch, and circuitry. The firstpower supply system includes a first electrical energy accumulator andan electric load coupled to the first electrical energy accumulator. Thesecond power supply system includes a generator motor and a secondelectrical energy accumulator. The generator motor is coupled to theengine. The second electrical energy accumulator is able to be coupledto the generator motor. The first switch is configured to be controlledto a first turn-on state and a first turn-off state. The first turn-onstate includes coupling the first power supply system and the secondpower supply system to each other, and the first turn-off state includesisolating the first power supply system and the second power supplysystem from each other. The second switch is configured to be controlledto a second turn-on state and a second turn-off state. The secondturn-on state includes coupling the generator motor and the secondelectrical energy accumulator to each other, and the second turn-offstate includes isolating the generator motor and the second electricalenergy accumulator from each other. The circuitry is configured tocontrol the generator motor to a power generation state on the conditionthat a state of charge of the second electrical energy accumulator islower than a power generation threshold. The power generation thresholdis set at a first power generation threshold on the condition that thesecond switch is in a normal state. The power generation threshold isset at a second power generation threshold greater than the first powergeneration threshold on the condition that the second switch is in amalfunctioning state in which the second switch is rendered inoperativein the second turn-on state.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the technology and are incorporated in and constitute apart of this specification. The drawings illustrate exampleimplementations and, together with the specification, serve to explainthe principles of the technology.

FIG. 1 is a schematic diagram of a configuration example of a vehicle onwhich a vehicle power supply apparatus according to one implementationof the technology is mounted.

FIG. 2 is a circuit diagram of a simplified example of a power circuit.

FIG. 3 is a diagram of an example of a situation as to how currents aresupplied, with a starter generator controlled to a combustion powergeneration state.

FIG. 4 is a diagram of an example of a situation as to how currents aresupplied, with the starter generator controlled to a power generationsuspended state.

FIG. 5 is a diagram of an example of a situation as to how currents aresupplied, with the starter generator controlled to a regenerative powergeneration state.

FIG. 6 is a diagram of an example of a situation as to how currents aresupplied, with the starter generator controlled to a powering state.

FIG. 7 is a diagram of an example of a situation as to how currents aresupplied, with the starter generator controlled to the powering state.

FIG. 8 is a diagram of an example of a situation as to how currents aresupplied, in an engine initial start control.

FIG. 9 is a diagram of an example of a situation as to how currents aresupplied, in a lead battery supplementary charge control.

FIG. 10 is a flowchart of an example of an execution procedure in amalfunctioning determination control, part 1.

FIGS. 11A and 11B are diagrams of examples of situations as to howcurrents are supplied, in executing the malfunctioning determinationcontrol, part 1.

FIG. 12 is a flowchart of an example of an execution procedure in amalfunctioning determination control, part 2.

FIGS. 13A and 13B are diagrams of examples of situations as to howvoltages are applied, in executing the malfunctioning determinationcontrol, part 2.

FIG. 14 is a flowchart of an example of an execution procedure in amalfunctioning determination control, part 3.

FIGS. 15A and 15B are diagrams of examples of situations as to howcurrents are supplied, in executing the malfunctioning determinationcontrol, part 3.

FIG. 16 is a flowchart of an example of an execution procedure in amalfunctioning determination control, part 4.

FIGS. 17A and 17B are diagrams of examples of situations as to howcurrents are supplied, in executing the malfunctioning determinationcontrol, part 4.

FIG. 18 is a flowchart of an example of an execution procedure in amalfunctioning determination control, part 5.

FIGS. 19A and 19B are diagrams of examples of situations as to howcurrents are supplied, in executing the malfunctioning determinationcontrol, part 5 or a malfunctioning determination control, part 6.

FIG. 20 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 6.

FIG. 21 is a flowchart of an example of an execution procedure in amalfunctioning determination control, part 7.

FIGS. 22A and 22B are diagrams of examples of situations as to howcurrents are supplied, in executing the malfunctioning determinationcontrol, part 7 or a malfunctioning determination control, part 8.

FIG. 23 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 8.

FIG. 24 is a flowchart of an example of an execution procedure in afail-safe control.

FIG. 25 is a timing chart of an example of an operation state of a powerunit in a slip control of a lock up clutch on coasting.

FIG. 26 is a diagram of examples of a power generation threshold S1 aand a suspension threshold S1 b to be set in a case where a switch SW2is normal.

FIG. 27 is a diagram of examples of a power generation threshold S2 aand a suspension threshold S2 b to be set in a case where the switch SW2is stuck ON.

DETAILED DESCRIPTION

In the following, some preferred but non-limiting implementations of thetechnology are described in detail with reference to the accompanyingdrawings. Note that sizes, materials, specific values, and any otherfactors illustrated in respective implementations are illustrative foreasier understanding of the technology, and are not intended to limitthe scope of the technology unless otherwise specifically stated.Further, elements in the following example implementations which are notrecited in a most-generic independent claim of the technology areoptional and may be provided on an as-needed basis. Throughout thepresent specification and the drawings, elements having substantiallythe same function and configuration are denoted with the same referencenumerals to avoid any redundant description. Further, elements that arenot directly related to the technology are unillustrated in thedrawings. The drawings are schematic and are not intended to be drawn toscale.

In a case where a switch in a vehicle power supply apparatus has amalfunction, it is difficult to control a coupling state of anaccumulator and a generator motor, resulting in difficulties in allowingthe vehicle power supply apparatus to function appropriately. Examplesof the malfunction may include that the switch is rendered inoperativein an ON state, i.e., that the switch is stuck ON. What is desired is,therefore, to control the generator motor appropriately in the casewhere the switch is stuck ON.

It is desirable to provide a vehicle power supply apparatus that makesit possible to control a generator motor appropriately in a case where aswitch is in a malfunctioning state in which the switch is renderedinoperative in an ON state.

[Vehicle Configuration]

FIG. 1 schematically illustrates a configuration example of a vehicle 11on which a vehicle power supply apparatus 10 according to oneimplementation of the technology is mounted. Referring to FIG. 1, on thevehicle 11, a power unit 13 may be mounted. The power unit 13 mayinclude an engine 12 that serves as a power source. The engine 12 mayinclude a crank shaft 14 to which a starter generator 16 is coupledthrough a belt mechanism 15. A transmission mechanism 18 may be alsocoupled to the engine 12 through a torque converter 17. One or morewheels 20 may be coupled to the transmission mechanism 18 through, forexample but not limited to, a differential mechanism 19.

In one implementation of the technology, the starter generator 16 mayserve as a “generator motor”.

The starter generator 16 coupled to the engine 12 may be a so-calledintegrated starter generator (ISG) that serves as a generator and anelectric motor. Not only may the starter generator 16 serve as thegenerator driven by the crank shaft 14, the starter generator 16 mayalso serve as the electric motor that drives the crank shaft 14. Forexample, the starter generator 16 may be controlled to a powering state,in a case of a restart of the engine 12 in an idling stop control, or ina case of assistance with the engine 12 at the time of, for example, astart and acceleration. Thus, the starter generator 16 may serve as theelectric motor.

The starter generator 16 may include a stator 30 and a rotor 31. Thestator 30 may include a stator coil. The rotor 31 may include a fieldcoil. The starter generator 16 may further include an ISG controller 32,in order to control energized states of the stator coil and the fieldcoil. The ISG controller 32 may include an inverter, a regulator, amicrocomputer, various sensors, and other parts. Allowing the ISGcontroller 32 to control the energized states of the field coil and thestator coil causes a control of, for example but not limited to, a powergeneration voltage, power generation torque, and powering torque of thestarter generator 16. It is to be noted that the ISG controller 32 mayhave a function of detecting a terminal voltage of the starter generator16. In the following, the terminal voltage of the starter generator 16is also referred to the power generation voltage of the startergenerator 16, or an applied voltage to the starter generator 16.

In one implementation of the technology, the terminal voltage of thestarter generator 16 may serve as a “voltage of the generator motor”.

The power unit 13 may include a starter motor 33 that brings the engine12 to starting rotation. The starter motor 33 may include a pinion 34.The pinion 34 is able to move between a protruding position and aretreating position. At the protruding position, the pinion 34 isengaged with a ring gear 35 of the torque converter 17. At theretreating position, the engagement of the pinion 34 with the ring gear35 is released. As described later, an occupant operates, e.g., pressesdown, a starter button 36, and thereupon, a starter relay 37 is switchedto an ON state. The starter relay 37 may control energization of thestarter motor 33. Thus, the starter motor 33 is energized through thestarter relay 37, causing the pinion 34 of the starter motor 33 to moveto the protruding position and to rotate. Moreover, the vehicle 11 mayinclude an engine controller 38 in order to control the starter motor 33through the starter relay 37. The engine controller 38 may include, forexample but not limited to, a microcomputer. The engine controller 38may control not only the starter relay 37 but also engine auxiliaries 39such as a throttle valve, an injector, and an ignition device.

As described, the vehicle 11 in the figures may include, as the electricmotor that brings the engine 12 to the starting rotation, the startergenerator 16 and the starter motor 33. The starting rotation of theengine 12 is performed with the use of the starter generator 16, in acase of the restart of the engine 12 by the idling stop control, i.e.,in a case where the engine 12 is stopped because a stop condition issatisfied while the engine 12 is in operation, and the engine 12 isrestarted because a start condition is satisfied while the engine 12 isstopped. Meanwhile, the starting rotation of the engine 12 is performedwith the use of the starter motor 33, in a case where a control systemof the vehicle 11 is started up to cause an initial start of the engine12, i.e., in a case where the occupant operates the starter button 36 tostart the engine 12.

The torque converter 17 may further include a lock up clutch 40.Controlling the lock up clutch 40 to an engaged state causes the engine12 and the transmission mechanism 18 to be coupled through the lock upclutch 40. Meanwhile, controlling the lock up clutch 40 to a disengagedstate causes the engine 12 and the transmission mechanism 18 to becoupled through the torque converter 17. Moreover, the lock up clutch 40may be able to be controlled not only to the engaged state and thedisengaged state, but also to a slip state. In order to switch anoperation state of the lock up clutch 40, a valve unit 41 may be coupledto the torque converter 17, and a transmission controller 42 may becoupled to the valve unit 41. The valve unit 41 may include, for examplebut not limited to, a solenoid valve and an oil path. The transmissioncontroller 42 may include, for example but not limited to, amicrocomputer.

[Power Circuit]

The vehicle power supply apparatus 10 may include a power circuit 50,description of which is given below. FIG. 2 is a circuit diagram of asimplified example of the power circuit 50. Referring to FIG. 2, thepower circuit 50 may include a lead battery 51 and a lithium ion battery52. The lead battery 51 may be electrically coupled to the startergenerator 16. The lithium ion battery 52 may be electrically coupled, inparallel with the lead battery 51, to the starter generator 16. It is tobe noted that a terminal voltage of the lithium ion battery 52 may behigher in design than a terminal voltage of the lead battery 51, inorder to positively cause discharge of the lithium ion battery 52.Moreover, internal resistance of the lithium ion battery 52 may be lowerin design than internal resistance of the lead battery 51, in order topositively cause charge and the discharge of the lithium ion battery 52.

In one implementation of the technology, the lead battery 51 may serveas a “first electrical energy accumulator”. In one implementation of thetechnology, the lithium ion battery 52 may serve as a “second electricalenergy accumulator”.

A positive electrode line 53 may be coupled to a positive electrodeterminal 16 a of the starter generator 16. A positive electrode line 54may be coupled to a positive electrode terminal 52 a of the lithium ionbattery 52. A positive electrode line 56 may be coupled to a positiveelectrode terminal 51 a of the lead battery 51 through a positiveelectrode line 55. The positive electrode lines 53, 54, and 56 may becoupled to one another through a connection point 57. Moreover, anegative electrode line 58 may be coupled to a negative electrodeterminal 16 b of the starter generator 16. A negative electrode line 59may be coupled to a negative electrode terminal 52 b of the lithium ionbattery 52. A negative electrode line 60 may be coupled to a negativeelectrode terminal 51 b of the lead battery 51. The negative electrodelines 58, 59, and 60 may be coupled to one another through a referencepotential point 61.

As illustrated in FIG. 1, to the positive electrode line 55 of the leadbattery 51, coupled may be a positive electrode line 62. To the positiveelectrode line 62, coupled may be a group of electric devices 64including electric devices 63 such as various actuators and variouscontrollers. Moreover, on the negative electrode line 60 of the leadbattery 51, provided may be a battery sensor 65. The battery sensor 65may have a function of detecting a charge state and a discharge state ofthe lead battery 51. Non-limiting examples of the charge state and thedischarge state of the lead battery 51 may include a charge current, adischarge current, the terminal voltage, a state of charge SOC of thelead battery 51. It is to be noted that the state of charge SOC refersto a ratio of an amount of charged power to a designed capacity of abattery.

In one implementation of the technology, the electric devices 63 mayeach serve as an “electric load”.

The power circuit 50 may include a first power supply system 71 and asecond power supply system 72. The first power supply system 71 includesthe lead battery 51 and the electric devices 63. The second power supplysystem 72 includes the lithium ion battery 52 and the starter generator16. The first power supply system 71 and the second power supply system72 may be coupled to each other through the positive electrode line 56.On the positive electrode line 56, provided may be an electric powerfuse 73 and a switch SW1. The electric power fuse 73 is configured to bemelted down by an excessive current. The switch SW1 is configured to becontrolled to an ON state and an OFF state. Moreover, on the positiveelectrode line 54 of the lithium ion battery 52, provided may be aswitch SW2. The switch SW2 is configured to be controlled to an ON stateand an OFF state.

In one implementation of the technology, the switch SW1 may serve as a“first switch”, and the switch SW2 may serve as a “second switch”. Inone implementation of the technology, the ON state of the switch SW1 mayserve as a “first turn-on state”, and the OFF state of the switch SW1may serve as a “first turn-off state”. In one implementation of thetechnology, the ON state of the switch SW2 may serve as a “secondturn-on state”, and the OFF state of the switch SW2 may serve as a“second turn-off state”.

Controlling the switch SW1 to the ON state makes it possible to couplethe first power supply system 71 and the second power supply system 72to each other. Controlling the switch SW1 to the OFF state makes itpossible to isolate the first power supply system 71 and the secondpower supply system 72 from each other. Moreover, controlling the switchSW2 to the ON state makes it possible to couple the starter generator 16and the lithium ion battery 52 to each other. Controlling the switch SW2to the OFF state makes it possible to isolate the starter generator 16and the lithium ion battery 52 from each other.

The switches SW1 and SW2 may each be a switch including a semiconductorelement such as a metal oxide semiconductor field effect transistor(MOSFET), or alternatively the switches SW1 and SW2 may each be a switchthat causes a contact to mechanically open or close with the use of, forexample but not limited to, electromagnetic force. The ON state of theswitches SW1 and SW2 refers to an energized state that forms electricalcoupling, or a conductive state. The OFF state of the switches SW1 andSW2 refers to a non-energized state that forms electrical isolation, ora cutoff state. It is to be noted that the switches SW1 and SW2 may bealso referred to as, for example, a relay or a contactor.

As illustrated in FIG. 1, the power circuit 50 may include a batterymodule 74. The battery module 74 may include not only the lithium ionbattery 52 but also the switches SW1 and SW2. The battery module 74 mayfurther include a battery controller 75. The battery controller 75 mayinclude, for example but not limited to, a microcomputer and varioussensors. The battery controller 75 may have a function of monitoring,for example but not limited to, a state of charge SOC, a charge current,a discharge current, the terminal voltage, a cell temperature, and theinternal resistance of the lithium ion battery 52. The batterycontroller 75 may also have a function of controlling the switches SW1and SW2.

[Control System]

As illustrated in FIG. 1, the vehicle power supply apparatus 10 mayinclude a main controller 80. The main controller 80 is provided for acooperative control of, for example but not limited to, the power unit13 and the power circuit 50. The main controller 80 may include, forexample but not limited to, a microcomputer. The main controller 80 mayinclude an engine control unit 81, an ISG control unit 82, a firstswitch control unit 83, a second switch control unit 84, and amalfunctioning determination unit 85. The engine control unit 81 maycontrol the engine 12. The ISG control unit 82 may control the startergenerator 16. The first switch control unit 83 may control the switchSW1. The second switch control unit 84 may control the switch SW2. Themalfunctioning determination unit 85 may determine whether or not theswitch SW2 is in a malfunctioning state. The main controller 80 mayfurther include a starter control unit 86 and a clutch control unit 87.The starter control unit 86 may control the starter motor 33. The clutchcontrol unit 87 may control the lock up clutch 40. The main controller80 may further include an idling control unit 88, an assistance controlunit 89, and a slip control unit 90. The idling control unit 88 mayexecute the idling stop control described later. The assistance controlunit 89 may execute a motor assistance control described later. The slipcontrol unit 90 may execute a slip control of the lock up clutch oncoasting described later. The main controller 80 may further include,for example but not limited to, a fail-safe control unit 91. Thefail-safe control unit 91 may execute a fail-safe control describedlater.

In one implementation of the technology, the ISG control unit 82 mayserve as a “generator motor controller”. In one implementation of thetechnology, the slip control of the lock up clutch on the coasting mayserve as a “slip control of the lock up clutch”.

The main controller 80, the ISG controller 32, the engine controller 38,the transmission controller 42, and the battery controller 75 may becommunicatively coupled to one another through an on-vehicle network 92such as a controller area network (CAN) and a local interconnect network(LIN). The main controller 80 may control the power unit 13, the powercircuit 50, and other parts on the basis of information from thecontrollers and the sensors. It is to be noted that the main controller80 may control the starter generator 16 through the ISG controller 32,and control the switches SW1 and SW2 through the battery controller 75.Moreover, the main controller 80 may control the engine 12 and thestarter motor 33 through the engine controller 38, and control the lockup clutch 40 through the transmission controller 42.

[Power Generation Control of Starter Generator]

Description is given next of a power generation control of the startergenerator 16. The power generation control may be made by the maincontroller 80. The ISG control unit 82 of the main controller 80 maysupply a control signal to the ISG controller 32, to control the startergenerator 16 to a power generation state or the powering state. Thepower generation state of the starter generator 16 may include acombustion power generation state and a regenerative power generationstate described later. For example, in a case where the state of chargeSOC of the lithium ion battery 52 lowers, the ISG control unit 82 mayraise the power generation voltage of the starter generator 16, tocontrol the starter generator 16 to the combustion power generationstate. In a case where the state of charge SOC of the lithium ionbattery 52 increases, the ISG control unit 82 may lower the powergeneration voltage of the starter generator 16, to control the startergenerator 16 to a power generation suspended state. It is to be notedthat in FIG. 3 and subsequent figures which are described below, thestarter generator 16 is abbreviated to “ISG”.

FIG. 3 illustrates an example of a situation as to how currents aresupplied, with the starter generator 16 controlled to the combustionpower generation state. In one specific but non-limiting example, in acase where the state of charge SOC of the lithium ion battery 52 islower than a predetermined lower limit, the starter generator 16 may bedriven, by engine power, for power generation, in order to charge thelithium ion battery 52 and to increase the state of charge SOC. Thus, incontrolling the starter generator 16 to the combustion power generationstate, the power generation voltage of the starter generator 16 may beraised to a greater value than the terminal voltages of the lead battery51 and the lithium ion battery 52. In this way, as denoted by blackarrows in FIG. 3, currents may be supplied from the starter generator 16to, for example, the lithium ion battery 52, the group of the electricdevices 64, and the lead battery 51, causing the lithium ion battery 52and the lead battery 51 to be charged slowly. It is to be noted that thecombustion power generation state of the starter generator 16 meansallowing, by the engine power, the starter generator 16 to generatepower, i.e., causing fuel combustion inside the engine 12 to allow thestarter generator 16 to generate power.

FIG. 4 illustrates an example of a situation as to how currents aresupplied, with the starter generator 16 controlled to the powergeneration suspended state. In one specific but non-limiting example, ina case where the state of charge SOC of the lithium ion battery 52 ishigher than a predetermined upper limit, driving the starter generator16, by the engine power, for the power generation may be stopped, inorder to positively cause the discharge of the lithium ion battery 52.Thus, in controlling the starter generator 16 to the power generationsuspended state, the power generation voltage of the starter generator16 may be lowered to a smaller value than the terminal voltages of thelead battery 51 and the lithium ion battery 52. In this way, as denotedby black arrows in FIG. 4, a current may be supplied from the lithiumion battery 52 to the group of the electric devices 64. This makes itpossible to suppress or stop the driving of the starter generator 16 forthe power generation, leading to reduction in an engine load. It is tobe noted that it suffices for the power generation voltage of thestarter generator 16 in the power generation suspended state to be apower generation voltage that allows the lithium ion battery 52 todischarge. For example, the power generation voltage of the startergenerator 16 may be controlled to 0 (zero) V, or alternatively, thepower generation voltage of the starter generator 16 may be controlledto a greater value than 0 (zero) V.

As mentioned above, the ISG control unit 82 of the main controller 80may control the starter generator 16 to the combustion power generationstate or the power generation suspended state on the basis of the stateof charge SOC. Meanwhile, at the time of vehicle deceleration, it isdesirable to recover much kinetic energy to enhance fuel consumptionperformance. Therefore, at the time of the vehicle deceleration, thepower generation voltage of the starter generator 16 may be raisedconsiderably, to control the starter generator 16 to the regenerativepower generation state. This makes it possible to increasepower-generated electric power of the starter generator 16. It istherefore possible to positively convert the kinetic energy to electricenergy and to recover the electric energy, leading to higher energyefficiency of the vehicle 11 and enhancement in the fuel consumptionperformance. A determination as to whether or not to executeregenerative power generation as described above may be made on thebasis of, for example but not limited to, operation states of anaccelerator pedal and a brake pedal. For example, on decelerated travelwith a release of stepping down of the accelerator pedal, or ondecelerated travel with stepping down of the brake pedal, the startergenerator 16 may be controlled to the regenerative power generationstate. FIG. 5 illustrates an example of a situation as to how currentsare supplied, with the starter generator 16 controlled to theregenerative power generation state. In controlling the startergenerator 16 to the regenerative power generation state, the powergeneration voltage of the starter generator 16 may be raised to a highervalue than in the combustion power generation state as mentioned above.Thus, an applied voltage to the lithium ion battery 52 is raised to agreater value than the terminal voltage. This causes large currentsupply from the starter generator 16 to the lithium ion battery 52 andthe lead battery 51, as denoted by black arrows in FIG. 5, resulting inrapid charge of the lithium ion battery 52 and the lead battery 51.Moreover, because the internal resistance of the lithium ion battery 52is smaller than the internal resistance of the lead battery 51, most ofthe power-generated current is supplied to the lithium ion battery 52.

It is to be noted that as illustrated in FIGS. 3 to 5, in controllingthe starter generator 16 to the combustion power generation state, theregenerative power generation state, and the power generation suspendedstate, the switches SW1 and SW2 may be kept in the ON state. In otherwords, in the vehicle power supply apparatus 10, it is possible tocontrol the charge and the discharge of the lithium ion battery 52solely by controlling the power generation voltage of the startergenerator 16 without making a switching control of the switches SW1 andSW2. Hence, it is possible to easily control the charge and thedischarge of the lithium ion battery 52, and to enhance durability ofthe switches SW1 and SW2.

[Engine Restart in Idling Stop Control]

The idling control unit 88 of the main controller 80 may execute theidling stop control. The idling stop control includes automaticallystopping and restarting the engine 12. The idling control unit 88 mayexecute, for example but not limited to, a fuel cut to stop the engine12, in the case where the predetermined stop condition is satisfiedwhile the engine 12 is in operation. The idling control unit 88 maybring the starter generator 16 to rotation to restart the engine 12, inthe case where the predetermined start condition is satisfied while theengine 12 is stopped. Non-limiting examples of the stop condition of theengine 12 may include that a vehicle speed is lower than a predeterminedvalue, with the brake pedal being stepped down. Non-limiting examples ofthe start condition of the engine 12 may include that stepping down ofthe brake pedal is released, and that stepping down of the acceleratorpedal is started. It is to be noted that in executing the idling stopcontrol, the idling control unit 88 may supply a control signal to theengine control unit 81 and the ISG control unit 82, to control theengine 12 and the starter generator 16.

The idling control unit 88 may control the starter generator 16 to thepowering state, to bring the engine 12 to the starting rotation, in acase where the start condition is satisfied while the engine 12 isstopped in the idling stop control. FIG. 6 illustrates an example of asituation as to how currents are supplied, with the starter generator 16controlled to the powering state. As illustrated in FIG. 6, incontrolling the starter generator 16 to the powering state at therestart of the engine 12 in the idling stop control, the switch SW1 maybe switched from the ON state to the OFF state. In other words, inallowing the starter generator 16 to bring the engine 12 to the startingrotation, the switch SW1 may be switched to the OFF state, causing theisolation of the first power supply system 71 and the second powersupply system 72 from each other. This makes it possible to prevent aninstantaneous voltage drop with respect to the group of the electricdevices 64 of the first power supply system 71 even in a case with largecurrent supply from the lithium ion battery 52 to the starter generator16. It is therefore possible to allow the group of the electric devices64, without limitation, to function normally.

[Motor Assistance Control]

The assistance control unit 89 of the main controller 80 may control thestarter generator 16 to the powering state at the time of, for example,the start and the acceleration, to execute the motor assistance control.The motor assistance control includes allowing the starter generator 16to provide assistance with the engine 12. It is to be noted that inexecuting the motor assistance control, the assistance control unit 89may supply a control signal to the ISG control unit 82, to control thestarter generator 16.

FIG. 7 illustrates an example of a situation as to how currents aresupplied, with the starter generator 16 controlled to the poweringstate. As illustrated in FIG. 7, in controlling the starter generator 16to the powering state in accompaniment with the motor assistancecontrol, the switches SW1 and SW2 may both be kept at the ON state.Thus, in the case where the starter generator 16 is allowed to provideassistance with the engine 12, controlling the switches SW1 and SW2 tothe ON state causes both the lead battery 51 and the lithium ion battery52 to be coupled to the group of the electric devices 64. This makes itpossible to stabilize a power supply voltage of the group of theelectric devices 64, leading to enhancement in reliability of thevehicle power supply apparatus 10.

As mentioned above, the switch SW1 may be switched to the OFF state atthe restart of the engine 12 by the starter generator 16. Meanwhile, theswitch SW1 may be kept at the ON state while the starter generator 16provides motor assistance. In other words, the restart of the engine 12means a situation that the starter generator 16 causes the engine 12that is stopped to start rotation. Such a situation may easily involvean increase in power consumption of the starter generator 16. Incontrast, the motor assistance means a situation that the startergenerator 16 may supplementarily drive the engine 12 that is rotating.Such a situation may involve reduction in the power consumption of thestarter generator 16. Because the power consumption of the startergenerator 16 is reduced as mentioned above in the motor assistancecontrol, keeping the switch SW1 at the ON state causes no large currentsupply from the lead battery 51 to the starter generator 16. It istherefore possible to stabilize the power supply voltage of the group ofthe electric devices 64.

[Engine Initial Start Control and Lead Battery Supplementary ChargeControl]

Described next is an engine initial start control that includes startingthe engine 12 with the use of the starter motor 33, following whichdescribed is a lead battery supplementary charge control to be executedby the starter generator 16 after an initial start of the engine 12.FIG. 8 illustrates an example of a situation as to how currents aresupplied, in the engine initial start control. FIG. 9 illustrates anexample of a situation as to how currents are supplied, in the leadbattery supplementary charge control.

In a case where the control system of the vehicle 11 is started up, tocause the initial start of the engine 12, i.e., in a case where theoperation of the starter button 36 starts the engine 12, the startermotor 33 may bring the engine 12 to the starting rotation. In the engineinitial start control, as illustrated in FIG. 8, the switch SW1 may becontrolled to the OFF state. The switch SW2 may be controlled to the OFFstate. The starter relay 37 may be controlled to an ON state. Thus,currents are supplied from the lead battery 51 to the starter motor 33,bringing the starter motor 33 to rotation, to start the engine 12.

Thus, the engine 12 is started by the starter motor 33, and thereupon,as illustrated in FIG. 9, the starter relay 37 may be switched to an OFFstate. The switch SW1 may be switched to the ON state. The startergenerator 16 may be controlled to the combustion power generation state.In other words, at the start of the engine 12, while the switch SW2 iskept at the OFF state, the switch SW1 may be switched to the ON state,and the starter generator 16 may be controlled to the combustion powergeneration state. This makes it possible to allow the starter generator16 to positively charge the lead battery 51, leading to restoration ofthe state of charge SOC of the lead battery 51 that tends to lowerduring a stop of the vehicle 11 or at the initial start of the engine12.

For example, during the stop of the vehicle 11, a dark current flowsfrom the lead battery 51 to the group of the electric devices 64. At theinitial start of the engine 12, a large current flows from the leadbattery 51 to the starter motor 33. Accordingly, the state of charge SOCof the lead battery 51 decreases gradually during the stop of thevehicle 11 and at the initial start of the engine 12. Executing the leadbattery supplementary charge control after the initial start of theengine 12 causes the restoration of the lowered state of charge SOC ofthe lead battery 51. It is to be noted that the lead batterysupplementary charge control may be continued for predetermined time, oralternatively, the lead battery supplementary charge control may becontinued until the state of charge SOC of the lead battery 51 isrestored to a predetermined value.

[Switch SW2 Malfunctioning Determination Control]

In the following, described is a malfunctioning determination control ofthe switch SW2 to be executed by the vehicle power supply apparatus 10.As mentioned above, the switch SW2 may be controlled to the ON state andthe OFF state in accordance with the operation state of the vehiclepower supply apparatus 10. However, in a case of a malfunctioning statein which the switch SW2 is rendered inoperative in the ON state, i.e.,the switch SW1 is stuck ON, it is difficult to allow the vehicle powersupply apparatus 10 to operate appropriately. Thus, the vehicle powersupply apparatus 10 according to this implementation of the technologymay execute one or more of parts 1 to 8 of the malfunctioningdetermination control as follows, to determine whether or not the switchSW2 is stuck ON.

As described later, in the malfunctioning determination control, parts 1to 8, the malfunctioning determination unit 85 of the main controller 80may determine whether or not the switch SW2 is stuck ON on the basis ofa current of the lead battery 51, a current of the lithium ion battery52, or a voltage of the starter generator 16, or any combinationthereof, while recognizing a control signal to be transmitted to thestarter generator 16, a control signal to be transmitted to the switchSW1, and a control signal to be transmitted to the switch SW2.

In one implementation of the technology, the control signal to betransmitted to the starter generator 16 may serve as a “first controlsignal”. In one implementation of the technology, the control signal tobe transmitted to the switch SW1 may serve as a “second control signal”.In one implementation of the technology, the control signal to betransmitted to the switch SW2 may serve as a “third control signal”.

It is to be noted that the ISG control unit 82 of the main controller 80may transmit the control signal to the starter generator 16 through theISG controller 32. Specific but non-limiting examples of the controlsignal to be transmitted to the starter generator 16 may include a powergeneration signal, a power generation suspension signal, and a poweringsignal. The power generation signal may control the starter generator 16to the combustion power generation state or the regenerative powergeneration state. The power generation suspension signal may control thestarter generator 16 to the power generation suspended state. Thepowering signal may control the starter generator 16 to the poweringstate.

The first switch control unit 83 of the main controller 80 may transmitthe control signal to the switch SW1 through the battery controller 75.Specific but non-limiting examples of the control signal to betransmitted to the switch SW1 may include an ON signal that controls theswitch SW1 to the ON state, and an OFF signal that controls the switchSW1 to the OFF state. The second switch control unit 84 of the maincontroller 80 may transmit the control signal to the switch SW2 throughthe battery controller 75. Specific but non-limiting examples of thecontrol signal to be transmitted to the switch SW2 may include an ONsignal that controls the switch SW2 to the ON state, and an OFF signalthat controls the switch SW2 to the OFF state.

(Malfunctioning Determination Control, Part 1)

FIG. 10 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 1. FIGS. 11A and 11B arediagrams of examples of situations as to how currents are supplied, inexecuting the malfunctioning determination control, part 1. FIG. 11Aillustrates the situation in a case where the switch SW2 is normal. FIG.11B illustrates the situation in a case where the switch SW2 is stuckON. It is to be noted that black arrows in FIGS. 11A and 11B indicatehow the currents are supplied.

Referring to FIG. 10, in step S10, the ON signal may be transmitted tothe switch SW1. In step S11, the OFF signal may be transmitted to theswitch SW2. In step S12, the power generation suspension signal may betransmitted to the starter generator 16. Thereafter, in step S13, adischarge current iLi_d to be discharged from the lithium ion battery 52may be detected. It is to be noted that the discharge current iLi_d ofthe lithium ion battery 52 may be detected by the battery controller 75.

In one implementation of the technology, the discharge current iLi_d mayserve as a “current of the second electrical energy accumulator”.

Thereafter, in step S14, a determination may be made as to whether ornot the discharge current iLi_d of the lithium ion battery 52 is greaterthan a predetermined threshold id1. In step S14, in a case where adetermination is made that the discharge current iLi_d is greater thanthe threshold id1 (Y in step S14), the flow may proceed to step S15. Instep S15, a determination may be made that the switch SW2 is stuck ON.Meanwhile, in step S14, in a case where a determination is made that thedischarge current iLi_d is equal to or smaller than the threshold id1 (Nin step S14), the flow may proceed to step S16. In step S16, adetermination may be made that the switch SW2 is in a normal state.

As illustrated in FIG. 11A, in the case where the switch SW2 is normal,the switch SW1 is controlled to the ON state. The switch SW2 iscontrolled to the OFF state. The starter generator 16 is controlled tothe power generation suspended state. In this case, the group of theelectric devices 64 is isolated from the lithium ion battery 52.Accordingly, the discharge current iLi_d of the lithium ion battery 52is 0 (zero) A.

In contrast, as illustrated in FIG. 11B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the ON state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the power generation suspended state. In this case, thegroup of the electric devices 64 is coupled to the lithium ion battery52. Accordingly, the discharge current iLi_d of the lithium ion battery52 increases in accordance with an operation state of the group of theelectric devices 64.

In other words, in the case where the switch SW2 is stuck ON, thedischarge current iLi_d of the lithium ion battery 52 becomes greaterthan in the case where the switch SW2 is normal. Accordingly, comparingthe discharge current iLi_d with the threshold id1 to determine theirmagnitude relation and grasping how the discharge current iLi_d isincreasing makes it possible to detect that the switch SW2 is stuck ON.It is to be noted that the threshold id1 may be set on the basis of, forexample but not limited to, experiments and simulation so as to grasphow the discharge current iLi_d is increasing.

(Malfunctioning Determination Control, Part 2)

FIG. 12 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 2. FIGS. 13A and 13B arediagrams of examples of situations as to how voltages are applied, inexecuting the malfunctioning determination control, part 2. FIG. 13Aillustrates the situation in the case where the switch SW2 is normal.FIG. 13B illustrates the situation in the case where the switch SW2 isstuck ON. It is to be noted that white outlined arrows in FIGS. 13A and13B indicate how the voltages are applied.

Referring to FIG. 12, in step S20, the OFF signal may be transmitted tothe switch SW1. In step S21, the OFF signal may be transmitted to theswitch SW2. In step S22, the power generation suspension signal may betransmitted to the starter generator 16. Thereafter, in step S23, aterminal voltage Visg to be applied to the starter generator 16 may bedetected. It is to be noted that the terminal voltage Visg to be appliedto the starter generator 16, i.e., the applied voltage Visg to thestarter generator 16, may be detected by the ISG controller 32.

In one implementation of the technology, the terminal voltage Visg mayserve as a “voltage of the generator motor”.

Thereafter, in step S24, a determination may be made as to whether ornot the applied voltage Visg to the starter generator 16 is greater thana predetermined threshold V1. In step S24, in a case where adetermination is made that the applied voltage Visg is greater than thethreshold V1 (Y in step S24), the flow may proceed to step S25. In stepS25, a determination may be made that the switch SW2 is stuck ON.Meanwhile, in step S24, in a case where a determination is made that theapplied voltage Visg is equal to or smaller than the threshold V1 (N instep S24), the flow may proceed to step S26. In step S26, adetermination may be made that the switch SW2 is in the normal state.

As illustrated in FIG. 13A, in the case where the switch SW2 is normal,the switch SW1 is controlled to the OFF state. The switch SW2 iscontrolled to the OFF state. The starter generator 16 is controlled tothe power generation suspended state. In this case, both the leadbattery 51 and the lithium ion battery 52 are isolated from the startergenerator 16. Accordingly, the applied voltage Visg to the startergenerator 16 is 0 (zero) V.

In contrast, as illustrated in FIG. 13B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the OFF state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the power generation suspended state. In this case, thelithium ion battery 52 is coupled to the starter generator 16.Accordingly, the applied voltage Visg to the starter generator 16 has avoltage value that corresponds to the terminal voltage of the lithiumion battery 52.

In other words, in the case where the switch SW2 is stuck ON, theapplied voltage Visg to the starter generator 16 becomes greater than inthe case where the switch SW2 is normal. Accordingly, comparing theapplied voltage Visg with the threshold V1 to determine their magnituderelation and grasping how the applied voltage Visg is increasing makesit possible to detect that the switch SW2 is stuck ON. It is to be notedthat the threshold V1 may be set on the basis of, for example but notlimited to, experiments and simulation so as to grasp how the appliedvoltage Visg is increasing.

The situation that the switch SW1 is controlled to the OFF state, theswitch SW2 is controlled to the OFF state, and the starter generator 16is controlled to the power generation suspended state may be exemplifiedby a situation that the engine initial start control is executed, asillustrated in FIG. 8. In other words, executing the malfunctioningdetermination control, part 2 together with execution of the engineinitial start control makes it possible to detect easily that the switchSW2 is stuck ON.

(Malfunctioning Determination Control, Part 3)

FIG. 14 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 3. FIGS. 15A and 15B arediagrams of examples of situations as to how currents are supplied, inexecuting the malfunctioning determination control, part 3. FIG. 15Aillustrates the situation in the case where the switch SW2 is normal.FIG. 15B illustrates the situation in the case where the switch SW2 isstuck ON. It is to be noted that black arrows in FIGS. 15A and 15Bindicate how the currents are supplied.

Referring to FIG. 14, in step S30, the ON signal may be transmitted tothe switch SW1. In step S31, the OFF signal may be transmitted to theswitch SW2. In step S32, the power generation signal may be transmittedto the starter generator 16. Thereafter, in step S33, a charge currentiLi_c to be charged in the lithium ion battery 52 may be detected. It isto be noted that the charge current iLi_c of the lithium ion battery 52may be detected by the battery controller 75.

In one implementation of the technology, the charge current iLi_c mayserve as a “current of the second electrical energy accumulator”.

Thereafter, in step S34, a determination may be made as to whether ornot the charge current iLi_c of the lithium ion battery 52 is greaterthan a predetermined threshold ic1. In step S34, in a case where adetermination is made that the charge current iLi_c is greater than thethreshold ic1 (Y in step S34), the flow may proceed to step S35. In stepS35, a determination may be made that the switch SW2 is stuck ON.Meanwhile, in step S34, in a case where a determination is made that thecharge current iLi_c is equal to or smaller than the threshold ic1 (N instep S34), the flow may proceed to step S36. In step S36, adetermination may be made that the switch SW2 is in the normal state.

As illustrated in FIG. 15A, in the case where the switch SW2 is normal,the switch SW1 is controlled to the ON state. The switch SW2 iscontrolled to the OFF state. The starter generator 16 is controlled tothe power generation state. In this case, the lithium ion battery 52 isisolated from the starter generator 16. Accordingly, the charge currentiLi_c to be charged in the lithium ion battery 52 is 0 (zero) A.

In contrast, as illustrated in FIG. 15B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the ON state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the power generation state. In this case, the lithium ionbattery 52 is coupled to the starter generator 16. Accordingly, thecharge current iLi_c flows to the lithium ion battery 52 from thestarter generator 16 engaged in the power generation.

In other words, in the case where the switch SW2 is stuck ON, the chargecurrent iLi_c of the lithium ion battery 52 becomes greater than in thecase where the switch SW2 is normal. Accordingly, comparing the chargecurrent iLi_c with the threshold ic1 to determine their magnituderelation and grasping how the charge current iLi_c is increasing makesit possible to detect that the switch SW2 is stuck ON. It is to be notedthat the threshold ic1 may be set on the basis of, for example but notlimited to, experiments and simulation so as to grasp how the chargecurrent iLi_c is increasing.

The situation that the switch SW1 is controlled to the ON state, theswitch SW2 is controlled to the OFF state, and the starter generator 16is controlled to the power generation state may be exemplified by asituation that the lead battery supplementary charge control isexecuted, as illustrated in FIG. 9. In other words, executing themalfunctioning determination control, part 3 together with execution ofthe lead battery supplementary charge control makes it possible todetect easily that the switch SW2 is stuck ON.

(Malfunctioning Determination Control, Part 4)

FIG. 16 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 4. FIGS. 17A and 17B arediagrams of examples of situations as to how currents are supplied, inexecuting the malfunctioning determination control, part 4. FIG. 17Aillustrates the situation in the case where the switch SW2 is normal.FIG. 17B illustrates the situation in the case where the switch SW2 isstuck ON. It is to be noted that black arrows in FIGS. 17A and 17Bindicate how the currents are supplied.

Referring to FIG. 16, in step S40, the OFF signal may be transmitted tothe switch SW1. In step S41, the OFF signal may be transmitted to theswitch SW2. In step S42, the power generation signal may be transmittedto the starter generator 16. Thereafter, in step S43, the charge currentiLi_c to be charged in the lithium ion battery 52 may be detected. It isto be noted that the charge current iLi_c of the lithium ion battery 52may be detected by the battery controller 75.

In one implementation of the technology, the charge current iLi_c mayserve as a “current of the second electrical energy accumulator”.

Thereafter, in step S44, a determination may be made as to whether ornot the charge current iLi_c of the lithium ion battery 52 is greaterthan a predetermined threshold ic2. In step S44, in a case where adetermination is made that the charge current iLi_c is greater than thethreshold ic2 (Y in step S44), the flow may proceed to step S45. In stepS45, a determination may be made that the switch SW2 is stuck ON.Meanwhile, in step S44, in a case where a determination is made that thecharge current iLi_c is equal to or smaller than the threshold ic2 (N instep S44), the flow may proceed to step S46. In step S46, adetermination may be made that the switch SW2 is in the normal state.

As illustrated in FIG. 17A, in the case where the switch SW2 is normal,the switch SW1 is controlled to the OFF state. The switch SW2 iscontrolled to the OFF state. The starter generator 16 is controlled tothe power generation state. In this case, the lithium ion battery 52 isisolated from the starter generator 16. Accordingly, the charge currentiLi_c to be charged in the lithium ion battery 52 is 0 (zero) A.

In contrast, as illustrated in FIG. 17B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the OFF state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the power generation state. In this case, the lithium ionbattery 52 is coupled to the starter generator 16. Accordingly, thecharge current iLi_c flows to the lithium ion battery 52 from thestarter generator 16 engaged in the power generation.

In other words, in the case where the switch SW2 is stuck ON, the chargecurrent iLi_c of the lithium ion battery 52 becomes greater than in thecase where the switch SW2 is normal. Accordingly, comparing the chargecurrent iLi_c with the threshold ic2 to determine their magnituderelation and grasping how the charge current iLi_c is increasing makesit possible to detect that the switch SW2 is stuck ON. It is to be notedthat the threshold ic2 may be set on the basis of, for example but notlimited to, experiments and simulation so as to grasp how the chargecurrent iLi_c is increasing.

(Malfunctioning Determination Control, Part 5)

FIG. 18 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 5. FIGS. 19A and 19B arediagrams of examples of situations as to how currents are supplied, inexecuting the malfunctioning determination control, part 5 or themalfunctioning determination control, part 6 described later. FIG. 19Aillustrates the situation in the case where the switch SW2 is normal.FIG. 19B illustrates the situation in the case where the switch SW2 isstuck ON. It is to be noted that black arrows in FIGS. 19A and 19Bindicate how the currents are supplied.

Referring to FIG. 18, in step S50, the ON signal may be transmitted tothe switch SW1. In step S51, the OFF signal may be transmitted to theswitch SW2. In step S52, the powering signal may be transmitted to thestarter generator 16. Thereafter, in step S53, a discharge current iLi_dto be discharged from the lithium ion battery 52 may be detected. It isto be noted that the discharge current iLi_d of the lithium ion battery52 may be detected by the battery controller 75. Thereafter, in stepS54, a determination may be made as to whether or not the dischargecurrent iLi_d of the lithium ion battery 52 is greater than apredetermined threshold id2. In step S54, in a case where adetermination is made that the discharge current iLi_d is greater thanthe threshold id2 (Y in step S54), the flow may proceed to step S55. Instep S55, a determination may be made that the switch SW2 is stuck ON.

In one implementation of the technology, the discharge current iLi_d mayserve as a “current of the second electrical energy accumulator”.

Meanwhile, in step S54, in a case where a determination is made that thedischarge current iLi_d is equal to or smaller than the threshold id2 (Nin step S54), the flow may proceed to step S56. In step S56, a dischargecurrent iPb_d to be discharged from the lead battery 51 may be detected.It is to be noted that the discharge current iPb_d of the lead battery51 may be detected by the battery sensor 65. Thereafter, in step S57, adetermination may be made as to whether or not the discharge currentiPb_d of the lead battery 51 is smaller than a predetermined thresholdid3. In step S57, in a case where a determination is made that thedischarge current iPb_d is smaller than the threshold id3 (Y in stepS57), the flow may proceed to step S55. In step S55, a determination maybe made that the switch SW2 is stuck ON.

In one implementation of the technology, the discharge current iPb_d mayserve as a “current of the first electrical energy accumulator”.

As described, in step S54, in the case where the determination is madethat the discharge current iLi_d of the lithium ion battery 52 isgreater than the threshold id2 (Y in step S54), or in step S57, in thecase where the determination is made that the discharge current iPb_d ofthe lead battery 51 is smaller than the threshold id3 (Y in step S57),the flow may proceed to step S55. In step S55, the determination may bemade that the switch SW2 is stuck ON. Meanwhile, in a case where in stepS54, a determination is made that the discharge current iLi_d of thelithium ion battery 52 is equal to or smaller than the threshold id2 andin step S57, a determination is made that the discharge current iPb_d ofthe lead battery 51 is equal to or greater than the threshold id3 (N instep S54 and N in step S57), the flow may proceed to step S58. In stepS58, a determination may be made that the switch SW2 is in the normalstate.

As illustrated in FIG. 19A, in the case where the switch SW2 is normal,the switch SW1 is controlled to the ON state. The switch SW2 iscontrolled to the OFF state. The starter generator 16 is controlled tothe powering state. In this case, the lithium ion battery 52 is isolatedfrom the starter generator 16. Accordingly, the discharge current iLi_dof the lithium ion battery 52 is 0 (zero) A.

In contrast, as illustrated in FIG. 19B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the ON state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the powering state. In this case, the lithium ion battery52 is coupled to the starter generator 16. Accordingly, the dischargecurrent iLi_d flows to the starter generator 16 from the lithium ionbattery 52.

In other words, in the case where the switch SW2 is stuck ON, thedischarge current iLi_d of the lithium ion battery 52 becomes greaterthan in the case where the switch SW2 is normal. Accordingly, comparingthe discharge current iLi_d with the threshold id2 to determine theirmagnitude relation and grasping how the discharge current iLi_d isincreasing makes it possible to detect that the switch SW2 is stuck ON.It is to be noted that the threshold id2 may be set on the basis of, forexample but not limited to, experiments and simulation so as to grasphow the discharge current iLi_d is increasing.

Moreover, as illustrated in FIG. 19A, in the case where the switch SW2is normal, the switch SW1 is controlled to the ON state. The switch SW2is controlled to the OFF state. The starter generator 16 is controlledto the powering state. In this case, the lithium ion battery 52 isisolated from the starter generator 16 while the lead battery 51 iscoupled to the starter generator 16. Accordingly, the discharge currentiPb_d flows to the starter generator 16 solely from the lead battery 51.

In contrast, as illustrated in FIG. 19B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the ON state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the powering state. In this case, both the lead battery 51and the lithium ion battery 52 are coupled to the starter generator 16.Accordingly, the discharge currents iPb_d and iLi_d flow to the startergenerator 16 respectively from the lead battery 51 and the lithium ionbattery 52.

As described, in the case where the switch SW2 is normal, the startergenerator 16 is provided with current supply solely from the leadbattery 51. Accordingly, the discharge current iPb_d of the lead battery51 tends to increase. Meanwhile, in the case where the switch SW2 isstuck ON, the starter generator 16 is provided with current supply fromboth the lead battery 51 and the lithium ion battery 52. Accordingly,the discharge current iPb_d of the lead battery 51 tends to decrease.

In other words, in the case where the switch SW2 is stuck ON, thedischarge current iPb_d of the lead battery 51 becomes smaller than inthe case where the switch SW2 is normal. Accordingly, comparing thedischarge current iPb_d with the threshold id3 to determine theirmagnitude relation and grasping how the discharge current iPb_d isdecreasing makes it possible to detect that the switch SW2 is stuck ON.It is to be noted that the threshold id3 may be set on the basis of, forexample but not limited to, experiments and simulation so as to grasphow the discharge current iPb_d is decreasing.

(Malfunctioning Determination Control, Part 6)

In the malfunctioning determination control, part 5 illustrated in FIG.18, the determination is made that the switch SW2 is stuck ON in thecase where the discharge current iLi_d of the lithium ion battery 52 isgreater than the threshold id2 (Y in step S54), or in the case where thedischarge current iPb_d of the lead battery 51 is smaller than thethreshold id3 (Y in step S57). However, this is non-limiting. In thefollowing, described is the malfunctioning determination control, part 6in which the determination is made that the switch SW2 is stuck ON in acase where the discharge current iLi_d of the lithium ion battery 52 isgreater than the threshold id2 and the discharge current iPb_d of thelead battery 51 is smaller than the threshold id3.

FIG. 20 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 6. Referring to FIG. 20, instep S60, the ON signal may be transmitted to the switch SW1. In stepS61, the OFF signal may be transmitted to the switch SW2. In step S62,the powering signal may be transmitted to the starter generator 16.

Thereafter, in step S63, the discharge current iLi_d to be dischargedfrom the lithium ion battery 52 may be detected. In step S64, thedischarge current iPb_d to be discharged from the lead battery 51 may bedetected. It is to be noted that the discharge current iLi_d of thelithium ion battery 52 may be detected by the battery controller 75. Thedischarge current iPb_d of the lead battery 51 may be detected by thebattery sensor 65.

In one implementation of the technology, the discharge current iLi_d mayserve as a “current of the second electrical energy accumulator”, andthe discharge current iPb_d may serve as a “current of the firstelectrical energy accumulator”.

Thereafter, in step S65, a determination may be made as to whether ornot the discharge current iLi_d of the lithium ion battery 52 is greaterthan the predetermined threshold id2. In step S65, in a case where adetermination is made that the discharge current iLi_d is greater thanthe threshold id2 (Y in step S65), the flow may proceed to step S66. Instep S66, a determination may be made as to whether or not the dischargecurrent iPb_d of the lead battery 51 is greater than the predeterminedthreshold id3. In step S66, in a case where a determination is made thatthe discharge current iPb_d is smaller than the threshold id3 (Y in stepS66), the flow may proceed to step S67. In step S67, a determination maybe made that the switch SW2 is stuck ON.

As described, in the case where in step S65, the determination is madethat the discharge current iLi_d is greater than the threshold id2, andin step S66, the determination is made that the discharge current iPb_dis smaller than the threshold id3 (Y in step S65 and Y in step S66), theflow may proceed to step S67. In step S67, the determination may be madethat the switch SW2 is stuck ON. Meanwhile, in step S65, in a case wherea determination is made that the discharge current iLi_d is equal to orsmaller than the threshold id2 (N in step S65), or in step S66, in acase where a determination is made that the discharge current iPb_d isequal to or greater than the threshold id3 (N in step S66), the flow mayproceed to step S68. In step S68, a determination may be made that theswitch SW2 is in the normal state.

As illustrated in FIG. 19A mentioned above, in the case where the switchSW2 is normal, the switch SW1 is controlled to the ON state. The switchSW2 is controlled to the OFF state. The starter generator 16 iscontrolled to the powering state. In this case, the lithium ion battery52 is isolated from the starter generator 16, and the lead battery 51 iscoupled to the starter generator 16. Accordingly, the discharge currentiLi_d of the lithium ion battery 52 is 0 (zero) A, while the dischargecurrent iPb_d flows to the starter generator 16 from the lead battery51.

In contrast, as illustrated in FIG. 19B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the ON state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the powering state. In this case, both the lead battery 51and the lithium ion battery 52 are coupled to the starter generator 16.Accordingly, the discharge current iPb_d flows to the starter generator16 from the lead battery 51, while the discharge current iLi_d flows tothe starter generator 16 from the lithium ion battery 52.

In other words, in the case where the switch SW2 is stuck ON, thedischarge current iLi_d of the lithium ion battery 52 becomes greaterthan in the case where the switch SW2 is normal, while the dischargecurrent iPb_d of the lead battery 51 becomes smaller than in the casewhere the switch SW2 is normal. Accordingly, comparing the dischargecurrent iLi_d with the threshold id2 to determine their magnituderelation and grasping how the discharge current iLi_d is increasing, andcomparing the discharge current iPb_d with the threshold id3 todetermine their magnitude relation and grasping how the dischargecurrent iPb_d is decreasing make it possible to detect that the switchSW2 is stuck ON. It is to be noted that the threshold id2 may be set onthe basis of, for example but not limited to, experiments and simulationso as to grasp how the discharge current iLi_d is increasing. It is tobe noted that the threshold id3 may be set on the basis of, for examplebut not limited to, experiments and simulation so as to grasp how thedischarge current iPb_d is decreasing.

(Malfunctioning Determination Control, Part 7)

FIG. 21 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 7. FIGS. 22A and 22B arediagrams of examples of situations as to how currents are supplied, inexecuting the malfunctioning determination control, part 7 or themalfunctioning determination control, part 8 described later. FIG. 22Aillustrates the situation in the case where the switch SW2 is normal.FIG. 22B illustrates the situation in the case where the switch SW2 isstuck ON. It is to be noted that black arrows in FIGS. 22A and 22Bindicate how the currents are supplied.

Referring to FIG. 21, in step S70, the OFF signal may be transmitted tothe switch SW1. In step S71, the OFF signal may be transmitted to theswitch SW2. In step S72, the powering signal may be transmitted to thestarter generator 16. Thereafter, in step S73, the discharge currentiLi_d to be discharged from the lithium ion battery 52 may be detected.It is to be noted that the discharge current iLi_d of the lithium ionbattery 52 may be detected by the battery controller 75. Thereafter, instep S74, a determination may be made as to whether or not the dischargecurrent iLi_d of the lithium ion battery 52 is greater than apredetermined threshold id4. In step S74, in a case where adetermination is made that the discharge current iLi_d is greater thanthe threshold id4 (Y in step S74), the flow may proceed to step S75. Instep S75, a determination may be made that the switch SW2 is stuck ON.

In one implementation of the technology, the discharge current iLi_d mayserve as a “current of the second electrical energy accumulator”.

Meanwhile, in step S74, in a case where a determination is made that thedischarge current iLi_d is equal to or smaller than the threshold id4 (Nin step S74), the flow may proceed to step S76. In step S76, theterminal voltage Visg to be applied to the starter generator 16 may bedetected. It is to be noted that the terminal voltage Visg to be appliedto the starter generator 16, i.e., the applied voltage Visg to thestarter generator 16, may be detected by the ISG controller 32.Thereafter, in step S77, a determination may be made as to whether ornot the applied voltage Visg to the starter generator 16 is greater thana predetermined threshold V2. In step S77, in a case where adetermination is made that the applied voltage Visg is greater than thethreshold V2 (Y in step S77), the flow may proceed to step S75. In stepS75, a determination may be made that the switch SW2 is stuck ON.

In one implementation of the technology, the terminal voltage Visg mayserve as a “voltage of the generator motor”.

Thus, in step S74, in the case where the determination is made that thedischarge current iLi_d of the lithium ion battery 52 is greater thanthe threshold id4 (Y in step S74), or in step S77, in the case where thedetermination is made that the applied voltage Visg to the startergenerator 16 is greater than the threshold V2 (Y in step S77), the flowmay proceed to step S75. In step S75, the determination may be made thatthe switch SW2 is stuck ON. Meanwhile, in a case where in step S74, adetermination is made that the discharge current iLi_d of the lithiumion battery 52 is equal to or smaller than the threshold id4, and instep S77, a determination is made that the applied voltage Visg to thestarter generator 16 is equal to or smaller than the threshold V2 (N instep S74 and N in step S77), the flow may proceed to step S78. In stepS78, a determination may be made that the switch SW2 is in the normalstate.

As illustrated in FIG. 22A, in the case where the switch SW2 is normal,the switch SW1 is controlled to the OFF state. The switch SW2 iscontrolled to the OFF state. The starter generator 16 is controlled tothe powering state. In this case, the lithium ion battery 52 is isolatedfrom the starter generator 16. Accordingly, the discharge current iLi_dof the lithium ion battery 52 is 0 (zero) A.

In contrast, as illustrated in FIG. 22B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the OFF state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the powering state. In this case, the lithium ion battery52 is coupled to the starter generator 16. Accordingly, the dischargecurrent iLi_d of the lithium ion battery 52 has a current value thatcorresponds to current consumption of the starter generator 16.

In other words, in the case where the switch SW2 is stuck ON, thedischarge current iLi_d of the lithium ion battery 52 becomes greaterthan in the case where the switch SW2 is normal. Accordingly, comparingthe discharge current iLi_d with the threshold id4 to determine theirmagnitude relation and grasping how the discharge current iLi_d isincreasing makes it possible to detect that the switch SW2 is stuck ON.It is to be noted that the threshold id4 may be set on the basis of, forexample but not limited to, experiments and simulation so as to grasphow the discharge current iLi_d is increasing.

As illustrated in FIG. 22A, in the case where the switch SW2 is normal,the switch SW1 is controlled to the OFF state. The switch SW2 iscontrolled to the OFF state. The starter generator 16 is controlled tothe powering state. In this case, both the lead battery 51 and thelithium ion battery 52 are isolated from the starter generator 16.Accordingly, the applied voltage Visg to the starter generator 16 is 0(zero) V.

In contrast, as illustrated in FIG. 22B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the OFF state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the powering state. In this case, the lithium ion battery52 is coupled to the starter generator 16. Accordingly, the appliedvoltage Visg to the starter generator 16 has the voltage value thatcorresponds to the terminal voltage of the lithium ion battery 52.

In other words, in the case where the switch SW2 is stuck ON, theapplied voltage Visg to the starter generator 16 becomes greater than inthe case where the switch SW2 is normal. Accordingly, comparing theapplied voltage Visg with the threshold V2 to determine their magnituderelation and grasping how the applied voltage Visg is increasing makesit possible to detect that the switch SW2 is stuck ON. It is to be notedthat the threshold V2 may be set on the basis of, for example but notlimited to, experiments and simulation so as to grasp how the appliedvoltage Visg is increasing.

(Malfunctioning Determination Control, Part 8)

In the malfunctioning determination control, part 7 illustrated in FIG.21, the determination is made that the switch SW2 is stuck ON in thecase where the discharge current iLi_d of the lithium ion battery 52 isgreater than the threshold id4 (Y in step S74), or in the case where theapplied voltage Visg to the starter generator 16 is greater than thethreshold V2 (Y in step S77). However, this is non-limiting. In thefollowings, described is the malfunctioning determination control, part8 in which the determination is made that the switch SW2 is stuck ON ina case where the discharge current iLi_d of the lithium ion battery 52is greater than the threshold id4, and the applied voltage Visg to thestarter generator 16 is greater than the threshold V2.

FIG. 23 is a flowchart of an example of an execution procedure in themalfunctioning determination control, part 8. Referring to FIG. 23, instep S80, the OFF signal may be transmitted to the switch SW1. In stepS81, the OFF signal may be transmitted to the switch SW2. In step S82,the powering signal may be transmitted to the starter generator 16.

Thereafter, in step S83, the discharge current iLi_d to be dischargedfrom the lithium ion battery 52 may be detected. In step S84, theterminal voltage Visg to be applied to the starter generator 16 may bedetected. It is to be noted that the discharge current iLi_d of thelithium ion battery 52 may be detected by the battery controller 75. Itis to be noted that the terminal voltage Visg to be applied to thestarter generator 16, i.e., the applied voltage Visg to the startergenerator 16, may be detected by the ISG controller 32.

In one implementation of the technology, the discharge current iLi_d mayserve as a “current of the second electrical energy accumulator”. In oneimplementation of the technology, the terminal voltage Visg may serve asa “voltage of the generator motor”.

Thereafter, in step S85, a determination may be made as to whether ornot the discharge current iLi_d of the lithium ion battery 52 is greaterthan the predetermined threshold id4. In step S85, in a case where adetermination is made that the discharge current iLi_d is greater thanthe threshold id4 (Y in step S85), the flow may proceed to step S86. Instep S86, a determination may be made as to whether or not the appliedvoltage Visg to the starter generator 16 is greater than thepredetermined threshold V2. In step S86, in a case where a determinationis made that the applied voltage Visg is greater than the threshold V2(Y in step S86), the flow may proceed to step S87. In step S87, adetermination may be made that the switch SW2 is stuck ON.

In this way, in the case where in step S85, the determination is madethat the discharge current iLi_d is greater than the threshold id4, andin step S86, the determination is made that the applied voltage Visg isgreater than the threshold V2 (Y in step S85 and Y in step S86), theflow may proceed to step S87. In step S87, the determination may be madethat the switch SW2 is stuck ON. Meanwhile, in step S85, in a case wherea determination is made that the discharge current iLi_d is equal to orsmaller than the threshold id4 (N in step S85), or in step S86, in acase where a determination is made that the applied voltage Visg isequal to or smaller than the threshold V2 (N in step S86), the flow mayproceed to step S88. In step S88, a determination may be made that theswitch SW2 is in the normal state.

As illustrated in FIG. 22A mentioned above, in the case where the switchSW2 is normal, the switch SW1 is controlled to the OFF state. The switchSW2 is controlled to the OFF state. The starter generator 16 iscontrolled to the powering state. In this case, both the lead battery 51and the lithium ion battery 52 are isolated from the starter generator16. Accordingly, the discharge current iLi_d of the lithium ion battery52 is 0 (zero) A, and the applied voltage Visg to the starter generator16 is 0 (zero) V.

In contrast, as illustrated in FIG. 22B, in the case where the switchSW2 is stuck ON, the switch SW1 is controlled to the OFF state. Theswitch SW2 is kept at the ON state. The starter generator 16 iscontrolled to the powering state. In this case, the lithium ion battery52 is coupled to the starter generator 16. Accordingly, the dischargecurrent iLi_d of the lithium ion battery 52 has the current value thatcorresponds to the current consumption of the starter generator 16.Moreover, because the lithium ion battery 52 is coupled to the startergenerator 16, the applied voltage Visg to the starter generator 16 hasthe voltage value that corresponds to the terminal voltage of thelithium ion battery 52.

In other words, in the case where the switch SW2 is stuck ON, thedischarge current iLi_d of the lithium ion battery 52 becomes greaterthan in the case where the switch SW2 is normal, and the applied voltageVisg to the starter generator 16 becomes greater than in the case wherethe switch SW2 is normal. Accordingly, comparing the discharge currentiLi_d with the threshold id4 to determine their magnitude relation andgrasping how the discharge current iLi_d is increasing, and comparingthe applied voltage Visg with the threshold V2 to determine theirmagnitude relation and grasping how the applied voltage Visg isincreasing make it possible to detect that the switch SW2 is stuck ON.It is to be noted that the threshold id4 may be set on the basis of, forexample but not limited to, experiments and simulation so as to grasphow the discharge current iLi_d is increasing. The threshold V2 may beset on the basis of, for example but not limited to, experiments andsimulation so as to grasp how the applied voltage Visg is increasing.

[Fail-Safe Control] (Inhibition of Idling Stop Control) (Inhibition ofMotor Assistance Control)

In the followings, description is given of a fail-safe control to beexecuted by the vehicle power supply apparatus 10. The fail-safe controlmay be executed by the fail-safe control unit 91 of the main controller80 in a case where, for example, any one of parts 1 to 8 of themalfunctioning determination control as described above is executed, andthereby the determination is made that the switch SW2 is stuck ON. It isto be noted that a method of determining whether the switch SW2 is stuckON is not limited to the malfunctioning determination control, parts 1to 8 as described above. Instead, the determination as to whether theswitch SW2 is stuck ON may be made by other methods.

FIG. 24 is a flowchart of an example of an execution procedure of thefail-safe control. Referring to FIG. 24, in step S90, a determinationmay be made as to whether or not the switch SW2 is stuck ON. In stepS90, in a case where a determination is made that the switch SW2 isstuck ON (Y in step S90), the flow may proceed to step S91. In step S91,the idling stop control may be inhibited, and the flow may proceed tostep S92. In step S92, the motor assistance control may be prohibited.

The situation that the switch SW2 is stuck ON is equivalent to asituation that it is impracticable to isolate the lithium ion battery 52from the power circuit 50. In this situation, an excessive decrease inthe state of charge SOC of the lithium ion battery 52 causes largeelectric power supply from the lead battery 51 to the lithium ionbattery 52, resulting in difficulties in maintaining the power supplyvoltage of the group of the electric devices 64. Accordingly, in thecase where the switch SW2 is stuck ON, the idling stop control and themotor assistance control may be inhibited as fail-safe operation, toinhibit the powering state of the starter generator 16. In this way, thedischarge of the lithium ion battery 52 is suppressed.

In other words, in the idling stop control, the starter generator 16 iscontrolled to the powering state at the restart of the engine 12. Thiscauses possibility that the starter generator 16 consumes much electricpower of the lithium ion battery 52. Accordingly, in the case where theswitch SW2 is stuck ON, the idling stop control may be inhibited, tosuppress the discharge of the lithium ion battery 52. This makes itpossible to suppress the state of charge SOC of the lithium ion battery52 from lowering. Hence, it is possible to stabilize the power supplyvoltage, and allow the group of the electric devices 64 to functionappropriately.

Likewise, in the motor assistance control, the starter generator 16 iscontrolled to the powering state at the time of, for example, the startand the acceleration. This causes the possibility that the startergenerator 16 consumes much electric power of the lithium ion battery 52.Accordingly, in the case where the switch SW2 is stuck ON, the motorassistance control may be inhibited, to suppress the discharge of thelithium ion battery 52. This makes it possible to suppress the state ofcharge SOC of the lithium ion battery 52 from lowering. Hence, it ispossible to stabilize the power supply voltage, and allow the group ofthe electric devices 64 to function appropriately.

(Inhibition of Slip Control of Lock Up Clutch on Coasting)

As illustrated in FIG. 24, in step S90, in the case where thedetermination is made that the switch SW2 is stuck ON (Y in step S90),the flow may proceed, through steps S91 and S92, to step S93. In stepS93, the slip control of the lock up clutch on the coasting may beinhibited. It is to be noted that the slip control of the lock up clutchon the coasting is a control to be executed on decelerated travel in alow vehicle speed region from viewpoint of reduction in an amount offuel consumption.

In one implementation of the technology, the slip control of the lock upclutch on the coasting may serve as a “slip control of the lock upclutch”.

Described below is the slip control of the lock up clutch on thecoasting, following which described is a reason for inhibition of theslip control of the lock up clutch on the coasting. FIG. 25 is a timingchart of an example of an operation state of the power unit 13 in theslip control of the lock up clutch on the coasting. In FIG. 25, the lockup clutch 40 is abbreviated to “L/U clutch” and the starter generator 16is abbreviated to “ISG”.

Referring to FIG. 25, on the coasting, i.e., gradual deceleration withthe release of the stepping down of the accelerator pedal, the lock upclutch 40 is controlled to the engaged state (reference characters a1).The injector of the engine auxiliaries 39 is controlled to the fuel cutstate (reference characters Ill). The starter generator 16 is controlledto the regenerative power generation state (reference characters c1).Thus, on the coasting, the injector is controlled to the fuel cut state,to stop the fuel injection and to reduce the amount of the fuelconsumption.

The coasting causes the vehicle speed to lower and to become smallerthan a predetermined first vehicle speed Ve1 (reference characters d1).Thereupon, the lock up clutch 40 may be controlled from the engagedstate to the slip state (reference characters a2), with the fuel cutstate of the injector continued (reference characters b2), and with theregenerative power generation state of the starter generator 16continued (reference characters c2). Furthermore, the coasting causesthe vehicle speed to lower and to become smaller than a second vehiclespeed Ve2 lower than the first vehicle speed Ve1 (reference charactersd2). Thereupon, the lock up clutch 40 may be controlled from the slipstate to the disengaged state (reference characters a3), and the startergenerator 16 may be controlled from the regenerative power generationstate to the powering state (reference characters c3), with the fuel cutstate of the injector continued (reference characters b3). Thereafter,the starter generator 16 may be controlled in the powering state forpredetermined time. Thereupon, the starter generator 16 may becontrolled from the powering state to the power generation suspendedstate (reference characters c4), and the injector may be controlled fromthe fuel cut state to the fuel injection state (reference charactersb4).

As described, in the slip control of the lock up clutch on the coasting,the starter generator 16 may be controlled to the powering state. Thismakes it possible to suppress the engine speed from lowering, as denotedby reference characters el. Hence, it is possible to avoid engine stalleven in a case where the restart of the fuel injection is retarded. Inother words, allowing the starter generator 16 to suppress the enginespeed from lowering makes it possible to continue the fuel cut state andto reduce the amount of the fuel consumption, even in a vehicle speedregion in which simply restarting the fuel injection may possibly causethe engine stall.

As mentioned above, in the slip control of the lock up clutch on thecoasting, the starter generator 16 may be controlled to the poweringstate. This causes possibility that the starter generator 16 consumesmuch electric power of the lithium ion battery 52. Accordingly, asillustrated in FIG. 24, in the case where the switch SW2 is stuck ON,the slip control of the lock up clutch on the coasting may be inhibited,to suppress the discharge of the lithium ion battery 52. This makes itpossible to suppress the state of charge SOC of the lithium ion battery52 from lowering. Hence, it is possible to stabilize the power supplyvoltage and to allow the group of the electric devices 64 to functionappropriately.

It is to be noted that in disengaging the lock up clutch 40 in the slipcontrol of the lock up clutch on the coasting, the lock up clutch 40 maybe switched from the slip state to the disengaged state, instead ofbeing switched from the engaged state to the disengaged state. Thismakes it possible to disengage the lock up clutch 40 quickly. Hence, itis possible to retard restart timing of the fuel injection whilepreventing the engine stall. Moreover, in the example illustrated in thefigures, in the slip control of the lock up clutch on the coasting, thestarter generator 16 is switched from the power generation state to thepowering state (reference characters c3), and the starter generator 16is switched from the powering state to the power generation suspendedstate (reference characters c4). However, this is non-limiting. Forexample, the starter generator 16 may be switched from the powergeneration suspended state to the powering state, or alternatively, thestarter generator 16 may be switched from the powering state to thepower generation state.

(Change of Power Generation Threshold)

As illustrated in FIG. 24, in step S90, in the case where thedetermination is made that the switch SW2 is stuck ON (Y in step S90),the flow may proceed, through steps S91 to S93, to step S94. In stepS94, a power generation threshold may be changed from a power generationthreshold S1 a to a power generation threshold S2 a. It is to be notedthat the power generation thresholds S1 a and S2 a are subjected tocomparison with the state of charge SOC of the lithium ion battery 52.In other words, the power generation thresholds S1 a and S2 a cause thestarter generator 16 to be switched from the power generation suspendedstate to the combustion power generation state.

In one implementation of the technology, the power generation thresholdS1 a may serve as a “first power generation threshold”. In oneimplementation of the technology, the power generation threshold S2 amay serve as a “second power generation threshold”.

In the following, described are details as to how the power generationthreshold is changed in step S94. As illustrated in FIG. 3 mentionedabove, in the case where the state of charge SOC of the lithium ionbattery 52 lowers, the starter generator 16 may be switched to thecombustion power generation state. In the combustion power generationstate of the starter generator 16, the power generation voltage may beraised to the greater value than the terminal voltage of the lithium ionbattery 52, causing the charge of the lithium ion battery 52. Moreover,as illustrated in FIG. 4, in the case where the state of charge SOC ofthe lithium ion battery 52 increases, the starter generator 16 may beswitched to the power generation suspended state. In the powergeneration suspended state of the starter generator 16, the powergeneration voltage may be lowered to the smaller value than the terminalvoltage of the lithium ion battery 52, to prompt the discharge of thelithium ion battery 52.

As described, in order to switch the starter generator 16 to thecombustion power generation state and the power generation suspendedstate on the basis of the state of charge SOC of the lithium ion battery52, the power generation thresholds S1 a and S2 a, and suspensionthresholds S1 b and S2 b may be set. The power generation thresholds S1a and S2 a, and the suspension thresholds S1 b and S2 b are to becompared with the state of charge SOC of the lithium ion battery 52.FIG. 26 illustrates examples of the power generation threshold S1 a andthe suspension threshold S1 b that are set in the case where the switchSW2 is normal. FIG. 27 illustrates examples of the power generationthreshold S2 a and the suspension threshold S2 b that are set in thecase where the switch SW2 is stuck ON.

As denoted by reference characters a1 in FIG. 26, in the case where thestate of charge SOC of the lithium ion battery 52 is lower than thepower generation threshold S1 a, the starter generator 16 may becontrolled to the combustion power generation state. The state of chargeSOC of the lithium ion battery 52 increases by the charge of the lithiumion battery 52, to reach the suspension threshold S1 b (referencecharacters a2). Thereupon, the starter generator 16 may be controlled tothe power generation suspended state. The state of charge SOC of thelithium ion battery 52 lowers by the discharge of the lithium ionbattery 52, to reach the power generation threshold S1 a (referencecharacters a3). Thereupon, the starter generator 16 may be controlledagain to the combustion power generation state. Thereafter, the state ofcharge SOC of the lithium ion battery 52 reaches the suspensionthreshold S1 b (reference characters a4), and thereupon, the startergenerator 16 may be controlled to the power generation suspended stateagain.

As described, in the case where the switch SW2 is normal, the powergeneration threshold S1 a and the suspension threshold S1 b may be setat small values. This makes it possible to keep low the state of chargeSOC of the lithium ion battery 52. Hence, it is possible to providesufficient vacant capacity a of the lithium ion battery 52, and tocontrol the starter generator 16 to the regenerative power generationstate on the decelerated travel, without missing a regenerationopportunity. In other words, as denoted by reference characters b1 to b2in FIG. 26, it is possible to control the starter generator 16 to theregenerative power generation state without missing the regenerationopportunity. Hence, it is possible to obtain much regenerative electricpower, leading to the higher energy efficiency of the vehicle 11.

In contrast, as illustrated in FIG. 27, in the case where the switch SW2is stuck ON, the power generation threshold S2 a and the suspensionthreshold S2 b may be set at greater values than in the case where theswitch SW2 is normal. In other words, the power generation threshold S1a may be set in the case where the switch SW2 is in the normal state,whereas the power generation threshold S2 a greater than the powergeneration threshold S1 a may be set in the case where the switch SW2 isstuck ON. Likewise, the suspension threshold S1 b may be set in the casewhere the switch SW2 is in the normal state, whereas the suspensionthreshold S2 b greater than the suspension threshold S1 b may be set inthe case where the switch SW2 is stuck ON.

Accordingly, in the case where the switch SW2 is stuck ON, as denoted byreference characters c1 in FIG. 27, the state of charge SOC of thelithium ion battery 52 becomes lower than the power generation thresholdS2 a, and thereupon, the starter generator 16 may be controlled to thecombustion power generation state. The state of charge SOC of thelithium ion battery 52 increases by the charge of the lithium ionbattery 52 to reach the suspension threshold S2 b (reference charactersc2), and thereupon, the starter generator 16 may be controlled to thepower generation suspended state. The state of charge SOC of the lithiumion battery 52 lowers by the discharge of the lithium ion battery 52 toreach the power generation threshold S2 a (reference characters c3), andthereupon, the starter generator 16 may be controlled again to thecombustion power generation state. Thereafter, the state of charge SOCof the lithium ion battery 52 reaches the suspension threshold S2 b(reference characters c4), and thereupon, the starter generator 16 maybe controlled again to the power generation suspended state.

As described, the power generation threshold S2 a in the case where theswitch SW2 is stuck ON may be set at the greater value than the powergeneration threshold S1 a in the case where the switch SW2 is normal.Hence, it is possible to keep relatively high the state of charge SOC ofthe lithium ion battery 52. In other words, the situation that theswitch SW2 is stuck ON is equivalent to the situation that it isimpracticable to isolate the lithium ion battery 52 from the powercircuit 50. In this situation, the excessive decrease in the state ofcharge SOC of the lithium ion battery 52 causes much electric powersupply from the lead battery 51 to the lithium ion battery 52, resultingin difficulties in maintaining the power supply voltage of the group ofthe electric devices 64. Accordingly, as illustrated in FIG. 24, in thecase where the switch SW2 is stuck ON, the power generation thresholdmay be changed, as the fail-safe operation, from the power generationthreshold S1 a to the power generation threshold S2 a. In this way, thedischarge of the lithium ion battery 52 is suppressed, to maintain thepower supply voltage of the group of the electric devices 64.

It is to be noted that in the example illustrated in FIG. 27, in thecase where the determination is made that the switch SW2 is stuck ON,the power generation threshold and the suspension threshold may be setrespectively at the higher power generation threshold S2 a and thehigher suspension threshold S2 b, to suppress the starter generator 16from being controlled to the power generation suspended state. However,this is non-limiting. For example, in the case where the determinationis made that the switch SW2 is stuck ON, the power generation thresholdS2 a and the suspension threshold S2 b may be set at greater values than100%, to inhibit the power generation suspended state of the startergenerator 16. In this case, it follows that the starter generator 16 iskept in the combustion power generation state.

Although some preferred implementations of the technology are describedabove by way of example with reference to the accompanying drawings, thetechnology is by no means limited to the implementations describedabove. It should be appreciated that modifications and alterations maybe made by persons skilled in the art without departing from the scopeas defined by the appended claims. In the forgoing exampleimplementations, the lead battery 51 may serve as the “first electricalenergy accumulator”, but this is non-limiting. Other kinds of batteriesor capacitors may be adopted as the “first electrical energyaccumulator”. Moreover, in the forgoing example implementations, thelithium ion battery 52 may serve as the “second electrical energyaccumulator”, but this is non-limiting. Other kinds of batteries orcapacitors may be adopted as the “second electrical energy accumulator”.Furthermore, in the forgoing example implementations illustrated inFIGS. 1 and 2, the switch SW2 is provided on the positive electrode line54 of the lithium ion battery 52, but this is non-limiting. For example,as denoted by an alternate long and short dashed line in FIG. 2, theswitch SW2 may be provided on the negative electrode line 59 of thelithium ion battery 52. In addition, in the forgoing exampleimplementations, the main controller 80 includes the engine control unit81, the ISG control unit 82, the first switch control unit 83, thesecond switch control unit 84, the starter control unit 86, the clutchcontrol unit 87, the idling control unit 88, the assistance control unit89, the slip control unit 90, the fail-safe control unit 91, and themalfunctioning determination unit 85, but this is non-limiting. Theengine control unit 81, the ISG control unit 82, the first switchcontrol unit 83, the second switch control unit 84, the starter controlunit 86, the clutch control unit 87, the idling control unit 88, theassistance control unit 89, the slip control unit 90, the fail-safecontrol unit 91, or the malfunctioning determination unit 85, or anycombination thereof may be provided in other controllers, oralternatively, the engine control unit 81, the ISG control unit 82, thefirst switch control unit 83, the second switch control unit 84, thestarter control unit 86, the clutch control unit 87, the idling controlunit 88, the assistance control unit 89, the slip control unit 90, thefail-safe control unit 91, and the malfunctioning determination unit 85may be distributed over a plurality of controllers.

As to the malfunctioning determination control, parts 1 to 8 illustratedin FIGS. 10 to 23, any one of parts 1 to 8 of the malfunctioningdetermination control may be executed alone. Alternatively, two or moreof parts 1 to 8 of the malfunctioning determination control may beexecuted in combination. For example, parts 1 and 2 of themalfunctioning determination control may be executed in combination. Inthis case, the determination may be made that the switch SW2 is stuck ONin a case where a determination is made, on the basis of themalfunctioning determination control, part 1, that the discharge currentiLi_d of the lithium ion battery 52 is greater than the threshold id1,and a determination is made, on the basis of the malfunctioningdetermination control, part 2, that the applied voltage Visg to thestarter generator 16 is greater than the threshold V1 (Y in step S14 andY in step S24).

In the fail-safe control illustrated in FIG. 24, in the case where thedetermination is made that the switch SW2 is stuck ON, the idling stopcontrol is inhibited; the motor assistance control is inhibited; theslip control of the lock up clutch on the coasting is inhibited; and thepower generation threshold is changed from the power generationthreshold S1 a to the power generation threshold S2 a. However, this isnon-limiting. For example, in the case where the determination is madethat the switch SW2 is stuck ON, the idling stop control, the motorassistance control, or the slip control of the lock up clutch on thecoasting, or any combination thereof may be inhibited. Moreover, in thecase where the determination is made that the switch SW2 is stuck ON,the power generation threshold may be changed from the power generationthreshold S1 a to the power generation threshold S2 a, withoutinhibiting the idling stop control, without limitation.

As described, the powering state of the starter generator 16 isinhibited in the case where the switch SW2 is in the malfunctioningstate in which the switch SW2 is rendered inoperative in the ON state.Hence, it is possible to control the starter generator 16 appropriatelyin the case where the switch SW2 is in the malfunctioning state in whichthe switch SW2 is rendered inoperative in the ON state.

Moreover, the power generation threshold S2 a greater than the powergeneration threshold S1 a is set as the power generation threshold inthe case where the switch SW2 is in the malfunctioning state in whichthe switch SW2 is rendered inoperative in the ON state. Hence, it ispossible to control the starter generator 16 appropriately in the casewhere the switch SW2 is in the malfunctioning state in which the switchSW2 is rendered inoperative in the ON state.

The main controller 80, the engine control unit 81, the ISG control unit82, the first switch control unit 83, the second switch control unit 84,the malfunctioning determination unit 85, the starter control unit 86,the clutch control unit 87, the idling control unit 88, the assistancecontrol unit 89, the slip control unit 90, and the fail-safe controlunit 91 illustrated in FIG. 1 are implementable by circuitry includingat least one semiconductor integrated circuit such as at least oneprocessor (e.g., a central processing unit (CPU)), at least oneapplication specific integrated circuit (ASIC), and/or at least onefield programmable gate array (FPGA). At least one processor isconfigurable, by reading instructions from at least one machine readablenon-transitory tangible medium, to perform all or a part of functions ofthe main controller 80, the engine control unit 81, the ISG control unit82, the first switch control unit 83, the second switch control unit 84,the malfunctioning determination unit 85, the starter control unit 86,the clutch control unit 87, the idling control unit 88, the assistancecontrol unit 89, the slip control unit 90, and the fail-safe controlunit 91. Such a medium may take many forms, including, but not limitedto, any type of magnetic medium such as a hard disk, any type of opticalmedium such as a CD and a DVD, any type of semiconductor memory (i.e.,semiconductor circuit) such as a volatile memory and a non-volatilememory. The volatile memory may include a DRAM and a SRAM, and thenonvolatile memory may include a ROM and a NVRAM. The ASIC is anintegrated circuit (IC) customized to perform, and the FPGA is anintegrated circuit designed to be configured after manufacturing inorder to perform, all or a part of the functions of the main controller80, the engine control unit 81, the ISG control unit 82, the firstswitch control unit 83, the second switch control unit 84, themalfunctioning determination unit 85, the starter control unit 86, theclutch control unit 87, the idling control unit 88, the assistancecontrol unit 89, the slip control unit 90, and the fail-safe controlunit 91 illustrated in FIG. 1.

It should be appreciated that modifications and alterations may be madeby persons skilled in the art without departing from the scope asdefined by the appended claims. The use of the terms first, second, etc.does not denote any order or importance, but rather the terms first,second, etc. are used to distinguish one element from another. Thetechnology is intended to include such modifications and alterations inso far as they fall within the scope of the appended claims or theequivalents thereof.

1. A vehicle power supply apparatus to be mounted on a vehicle thatincludes an engine, the vehicle power supply apparatus comprising: afirst power supply system including a first electrical energyaccumulator and an electric load coupled to the first electrical energyaccumulator; a second power supply system including a generator motorand a second electrical energy accumulator, the generator motor beingcoupled to the engine and being configured to be controlled to at leasta powering state, and the second electrical energy accumulator beingable to be coupled to the generator motor; a first switch configured tobe controlled to a first turn-on state and a first turn-off state, thefirst turn-on state including coupling the first power supply system andthe second power supply system to each other, and the first turn-offstate including isolating the first power supply system and the secondpower supply system from each other; a second switch configured to becontrolled to a second turn-on state and a second turn-off state, thesecond turn-on state including coupling the generator motor and thesecond electrical energy accumulator to each other, and the secondturn-off state including isolating the generator motor and the secondelectrical energy accumulator from each other; and a fail-safecontroller configured to inhibit the powering state of the generatormotor on a condition that the second switch is in a malfunctioning statein which the second switch is rendered inoperative in the second turn-onstate.
 2. The vehicle power supply apparatus according to claim 1,further comprising a generator motor controller that controls thegenerator motor to a power generation state on a condition that a stateof charge of the second electrical energy accumulator is lower than apower generation threshold, wherein the power generation threshold beingset at a first power generation threshold on a condition that the secondswitch is in a normal state, and being set at a second power generationthreshold greater than the first power generation threshold on acondition that the second switch is in the malfunctioning state in whichthe second switch is rendered inoperative in the second turn-on state.3. The vehicle power supply apparatus according to claim 1, furthercomprising an assistance controller that performs a motor assistancecontrol, the motor assistance control including controlling thegenerator motor to the powering state to provide assistance with theengine, wherein the fail-safe controller inhibits the motor assistancecontrol on the condition that the second switch is in the malfunctioningstate in which the second switch is rendered inoperative in the secondturn-on state.
 4. The vehicle power supply apparatus according to claim2, further comprising an assistance controller that performs a motorassistance control, the motor assistance control including controllingthe generator motor to the powering state to provide assistance with theengine, wherein the fail-safe controller inhibits the motor assistancecontrol on the condition that the second switch is in the malfunctioningstate in which the second switch is rendered inoperative in the secondturn-on state.
 5. The vehicle power supply apparatus according to claim1, further comprising: a lock up clutch provided in a torque converterof the vehicle and configured to be controlled to an engaged state, adisengaged state, and a slip state, the torque converter being coupledto the engine; and a slip controller configured to perform a slipcontrol of the lock up clutch, the slip control including switching thelock up clutch from the engaged state to the slip state on a conditionthat a vehicle speed is lower than a first vehicle speed, and switchingthe lock up clutch from the slip state to the disengaged state whilecontrolling the generator motor to the powering state on a conditionthat the vehicle speed is lower than a second vehicle speed lower thanthe first vehicle speed, wherein the fail-safe controller inhibits theslip control on the condition that the second switch is in themalfunctioning state in which the second switch is rendered inoperativein the second turn-on state.
 6. The vehicle power supply apparatusaccording to claim 2, further comprising: a lock up clutch provided in atorque converter of the vehicle and configured to be controlled to anengaged state, a disengaged state, and a slip state, the torqueconverter being coupled to the engine; and a slip controller configuredto perform a slip control of the lock up clutch, the slip controlincluding switching the lock up clutch from the engaged state to theslip state on a condition that a vehicle speed is lower than a firstvehicle speed, and switching the lock up clutch from the slip state tothe disengaged state while controlling the generator motor to thepowering state on a condition that the vehicle speed is lower than asecond vehicle speed lower than the first vehicle speed, wherein thefail-safe controller inhibits the slip control on the condition that thesecond switch is in the malfunctioning state in which the second switchis rendered inoperative in the second turn-on state.
 7. The vehiclepower supply apparatus according to claim 3, further comprising: a lockup clutch provided in a torque converter of the vehicle and configuredto be controlled to an engaged state, a disengaged state, and a slipstate, the torque converter being coupled to the engine; and a slipcontroller configured to perform a slip control of the lock up clutch,the slip control including switching the lock up clutch from the engagedstate to the slip state on a condition that a vehicle speed is lowerthan a first vehicle speed, and switching the lock up clutch from theslip state to the disengaged state while controlling the generator motorto the powering state on a condition that the vehicle speed is lowerthan a second vehicle speed lower than the first vehicle speed, whereinthe fail-safe controller inhibits the slip control on the condition thatthe second switch is in the malfunctioning state in which the secondswitch is rendered inoperative in the second turn-on state.
 8. Thevehicle power supply apparatus according to claim 4, further comprising:a lock up clutch provided in a torque converter of the vehicle andconfigured to be controlled to an engaged state, a disengaged state, anda slip state, the torque converter being coupled to the engine; and aslip controller configured to perform a slip control of the lock upclutch, the slip control including switching the lock up clutch from theengaged state to the slip state on a condition that a vehicle speed islower than a first vehicle speed, and switching the lock up clutch fromthe slip state to the disengaged state while controlling the generatormotor to the powering state on a condition that the vehicle speed islower than a second vehicle speed lower than the first vehicle speed,wherein the fail-safe controller inhibits the slip control on thecondition that the second switch is in the malfunctioning state in whichthe second switch is rendered inoperative in the second turn-on state.9. The vehicle power supply apparatus according to claim 2, furthercomprising an idling controller that performs an idling stop control,the idling stop control including stopping the engine on a basis of astop condition and afterwards controlling, on a basis of a startcondition, the generator motor to the powering state to start theengine, wherein the fail-safe controller inhibits the idling stopcontrol on the condition that the second switch is in the malfunctioningstate in which the second switch is rendered inoperative in the secondturn-on state.
 10. The vehicle power supply apparatus according to claim3, further comprising an idling controller that performs an idling stopcontrol, the idling stop control including stopping the engine on abasis of a stop condition and afterwards controlling, on a basis of astart condition, the generator motor to the powering state to start theengine, wherein the fail-safe controller inhibits the idling stopcontrol on the condition that the second switch is in the malfunctioningstate in which the second switch is rendered inoperative in the secondturn-on state.
 11. The vehicle power supply apparatus according to claim4, further comprising an idling controller that performs an idling stopcontrol, the idling stop control including stopping the engine on abasis of a stop condition and afterwards controlling, on a basis of astart condition, the generator motor to the powering state to start theengine, wherein the fail-safe controller inhibits the idling stopcontrol on the condition that the second switch is in the malfunctioningstate in which the second switch is rendered inoperative in the secondturn-on state.
 12. A vehicle power supply apparatus to be mounted on avehicle that includes an engine, the vehicle power supply apparatuscomprising: a first power supply system including a first electricalenergy accumulator and an electric load coupled to the first electricalenergy accumulator; a second power supply system including a generatormotor and a second electrical energy accumulator, the generator motorbeing coupled to the engine, and the second electrical energyaccumulator being able to be coupled to the generator motor; a firstswitch configured to be controlled to a first turn-on state and a firstturn-off state, the first turn-on state including coupling the firstpower supply system and the second power supply system to each other,and the first turn-off state including isolating the first power supplysystem and the second power supply system from each other; a secondswitch configured to be controlled to a second turn-on state and asecond turn-off state, the second turn-on state including coupling thegenerator motor and the second electrical energy accumulator to eachother, and the second turn-off state including isolating the generatormotor and the second electrical energy accumulator from each other; anda generator motor controller configured to control the generator motorto a power generation state on a condition that a state of charge of thesecond electrical energy accumulator is lower than a power generationthreshold, the power generation threshold being set at a first powergeneration threshold on a condition that the second switch is in anormal state, and being set at a second power generation thresholdgreater than the first power generation threshold on a condition thatthe second switch is in a malfunctioning state in which the secondswitch is rendered inoperative in the second turn-on state.
 13. Thevehicle power supply apparatus according to claim 1, further comprisinga malfunctioning determination unit that determines whether or not thesecond switch is in the malfunctioning state in which the second switchis rendered inoperative in the second turn-on state, on a basis of acurrent of the first electrical energy accumulator, a current of thesecond electrical energy accumulator, or a voltage of the generatormotor, or any combination thereof, while recognizing a first controlsignal to be transmitted to the generator motor, a second control signalto be transmitted to the first switch, and a third control signal to betransmitted to the second switch.
 14. The vehicle power supply apparatusaccording to claim 2, further comprising a malfunctioning determinationunit that determines whether or not the second switch is in themalfunctioning state in which the second switch is rendered inoperativein the second turn-on state, on a basis of a current of the firstelectrical energy accumulator, a current of the second electrical energyaccumulator, or a voltage of the generator motor, or any combinationthereof, while recognizing a first control signal to be transmitted tothe generator motor, a second control signal to be transmitted to thefirst switch, and a third control signal to be transmitted to the secondswitch.
 15. The vehicle power supply apparatus according to claim 3,further comprising a malfunctioning determination unit that determineswhether or not the second switch is in the malfunctioning state in whichthe second switch is rendered inoperative in the second turn-on state,on a basis of a current of the first electrical energy accumulator, acurrent of the second electrical energy accumulator, or a voltage of thegenerator motor, or any combination thereof, while recognizing a firstcontrol signal to be transmitted to the generator motor, a secondcontrol signal to be transmitted to the first switch, and a thirdcontrol signal to be transmitted to the second switch.
 16. The vehiclepower supply apparatus according to claim 4, further comprising amalfunctioning determination unit that determines whether or not thesecond switch is in the malfunctioning state in which the second switchis rendered inoperative in the second turn-on state, on a basis of acurrent of the first electrical energy accumulator, a current of thesecond electrical energy accumulator, or a voltage of the generatormotor, or any combination thereof, while recognizing a first controlsignal to be transmitted to the generator motor, a second control signalto be transmitted to the first switch, and a third control signal to betransmitted to the second switch.
 17. A vehicle power supply apparatusto be mounted on a vehicle that includes an engine, the vehicle powersupply apparatus comprising: a first power supply system including afirst electrical energy accumulator and an electric load coupled to thefirst electrical energy accumulator; a second power supply systemincluding a generator motor and a second electrical energy accumulator,the generator motor being coupled to the engine and being configured tobe controlled to at least a powering state, and the second electricalenergy accumulator being able to be coupled to the generator motor; afirst switch configured to be controlled to a first turn-on state and afirst turn-off state, the first turn-on state including coupling thefirst power supply system and the second power supply system to eachother, and the first turn-off state including isolating the first powersupply system and the second power supply system from each other; asecond switch configured to be controlled to a second turn-on state anda second turn-off state, the second turn-on state including coupling thegenerator motor and the second electrical energy accumulator to eachother, and the second turn-off state including isolating the generatormotor and the second electrical energy accumulator from each other; andcircuitry configured to inhibit the powering state of the generatormotor on a condition that the second switch is in a malfunctioning statein which the second switch is rendered inoperative in the second turn-onstate.
 18. A vehicle power supply apparatus to be mounted on a vehiclethat includes an engine, the vehicle power supply apparatus comprising:a first power supply system including a first electrical energyaccumulator and an electric load coupled to the first electrical energyaccumulator; a second power supply system including a generator motorand a second electrical energy accumulator, the generator motor beingcoupled to the engine, and the second electrical energy accumulatorbeing able to be coupled to the generator motor; a first switchconfigured to be controlled to a first turn-on state and a firstturn-off state, the first turn-on state including coupling the firstpower supply system and the second power supply system to each other,and the first turn-off state including isolating the first power supplysystem and the second power supply system from each other; a secondswitch configured to be controlled to a second turn-on state and asecond turn-off state, the second turn-on state including coupling thegenerator motor and the second electrical energy accumulator to eachother, and the second turn-off state including isolating the generatormotor and the second electrical energy accumulator from each other; andcircuitry configured to control the generator motor to a powergeneration state on a condition that a state of charge of the secondelectrical energy accumulator is lower than a power generationthreshold, the power generation threshold being set at a first powergeneration threshold on a condition that the second switch is in anormal state, and being set at a second power generation thresholdgreater than the first power generation threshold on a condition thatthe second switch is in a malfunctioning state in which the secondswitch is rendered inoperative in the second turn-on state.